For a long time radio represented a viable way to narrow cast advertising to a targeted audience – country music, rock and roll, classical, etc. – each representing a different set of demographics. Along comes the iPod (and other digital music devices), which offers the music listener nearly an unlimited variety of music formats – 90's hip-hop mixed with Bach and Beethoven – and all of a sudden radio stations are scrambling (pun intended) to mix up their music.
Apparently this latest shift started at a station in Canada call Jack which promoted itself as a "we play everything" station. Now stations in the lower 48 states are following suit. In the San Francisco Bay Area, 95.7 used to be the country music station and is now a "we play anything" station. This is one more example of a traditional media business being turned sideways by the digital age. For now it would seem radio stations that focus on talk and news are safe – but with XM and Sirius building customer bases – we can only safely conclude "the times they are a changing."